The present invention relates to external load operations, and more particularly to a winch system for use with Vertical Takeoff and Landing (VTOL) aircraft.
Vertical takeoff and landing (VTOL) aircraft such as, helicopters, co-axial counter rotating aircrafts, tilt-rotors, tilt-wings, etc., are unique in their ability to carry loads externally. Future military forces require enhanced vertical lift capabilities in a compact package. Super heavy lift (SHL) rotary-wing aircraft are generally defined as an aircraft with future payload capacities in the range of over 80,000 pounds of payload over a 400 mile range.
External load operations provide a rapid procedure to load, transport, and unload cargo. Frequently, one or more winch systems having cables with cargo hooks at an end thereof attach the payload to the aircraft for transportation. Winching systems having such future payload capacities need to be compact and relatively lightweight to package a multiple of winch systems within the VTOL aircraft. The multiple of winch systems are utilized to transport payloads expected of the future requirements.
Winch systems traditionally utilize a Fairlead (vertical and horizontal guide rollers) to smoothly spool the cable onto a drum. The diameter of the guide rollers of the Fairlead mechanisms are typically much smaller than the cables minimum bend radius (D/d) which limits the angular displacements to angles less than 3° to 5°. This is adequate for conventional, centrally aligned lift operations with minimal cable angle direction change, but cannot provide relatively large angles and short cable lengths necessary to meet future requirements in which a multiple of winch systems are attached to payloads expected of the future requirements. These payloads may include expensive vehicles that may be manned during flight such that the need for improvements in winch system drive technology, cable handling, cable angle capability, safety, and reliability become of increased importance.
Accordingly, it is desirable to provide a compact and relatively lightweight winch system capable of future load requirements which can be readily packaged within a VTOL aircraft for quad operation with relatively large cable angle direction change.